Free University of Bolzano, Piazza Università 1, 39100 Bolzano, Italy.
J Agric Food Chem. 2012 Nov 14;60(45):11268-73. doi: 10.1021/jf302846j. Epub 2012 Nov 6.
Stable isotope values were used to develop a new analytical approach enabling the simultaneous identification of milk samples either processed with different heating regimens or from different geographical origins. The samples consisted of raw, pasteurized (HTST), and ultrapasteurized (UHT) milk from different Italian origins. The approach consisted of the analysis of the isotope ratio of δ¹³C and δ¹⁵N for the milk samples and their fractions (fat, casein, and whey). The main finding of this work is that as the heat processing affects the composition of the milk fractions, changes in δ¹³C and δ¹⁵N were also observed. These changes were used as markers to develop pattern recognition maps based on principal component analysis and supervised classification models, such as linear discriminant analysis (LDA), multivariate regression (MLR), principal component regression (PCR), and partial least-squares (PLS). The results give proof of the concept that isotope ratio mass spectroscopy can discriminate simultaneously between milk samples according to their geographical origin and type of processing.
稳定同位素值被用来开发一种新的分析方法，能够同时识别经过不同加热处理或来自不同地理来源的牛奶样品。这些样品包括来自不同意大利产地的生奶、巴氏杀菌（HTST）和超巴氏杀菌（UHT）奶。该方法包括分析牛奶样品及其各部分（脂肪、乳清蛋白和酪蛋白）的 δ¹³C 和 δ¹⁵N 同位素比值。这项工作的主要发现是，随着热加工影响牛奶各部分的组成，也观察到 δ¹³C 和 δ¹⁵N 的变化。这些变化被用作标记物，根据主成分分析和监督分类模型（如线性判别分析（LDA）、多元回归（MLR）、主成分回归（PCR）和偏最小二乘（PLS））开发模式识别图。结果证明了这一概念，即同位素比质谱法可以根据其地理来源和加工类型同时对牛奶样品进行区分。
